{"product_id":"dell-h4x6x-2u-sliding-readyrails-ii","title":"Dell H4X6X \/ 770-BBIN B6 ReadyRails II 2U Sliding Rail Kit — for PowerEdge R720, R730, R740, R750 and Related 2U Chassis","description":"\u003cp\u003e\u003cstrong\u003eSliding ReadyRails II (B6) — the 2U service-extend kit, not the static \/ VersaRails \/ 1U kit\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eDell H4X6X \/ 770-BBIN — ReadyRails II 2U sliding rails for PowerEdge and related 2U chassis\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eDell Part Number:\u003c\/strong\u003e H4X6X\u003cbr\u003e\u003cstrong\u003eDell Order Code \/ MPN aliases:\u003c\/strong\u003e 770-BBIN, 0384R, 0H4X6X, XV104, 0XV104, 0PWN3, 61KCY, MMK10 (and related 0-prefixed stickers)\u003cbr\u003e\u003cstrong\u003eDescription:\u003c\/strong\u003e B6 ReadyRails II sliding rail kit for 2U systems — tool-less mount in 4-post square-hole and unthreaded round-hole racks; tooled mount in threaded-hole racks\u003c\/p\u003e\n\u003cp\u003eThis is the \u003cstrong\u003esliding\u003c\/strong\u003e rail kit — the one that lets you fully extend a 2U chassis out of the rack for service. Most sliding B6 kits support an optional cable management arm (CMA) so you can pull the system without disconnecting rear cables. The CMA is \u003cstrong\u003enot\u003c\/strong\u003e in this box; the kit ships with two rail assemblies and two hook-and-loop straps for basic rear cable routing.\u003c\/p\u003e\n\u003cp\u003eDell labels this mounting interface \u003cstrong\u003eReadyRails II\u003c\/strong\u003e and the rail identifier \u003cstrong\u003eB6\u003c\/strong\u003e (stamped on the rails). Older docs and BOMs may also show order codes like \u003cstrong\u003e770-BBIN\u003c\/strong\u003e or manufacturing stickers like \u003cstrong\u003e0H4X6X\u003c\/strong\u003e \/ \u003cstrong\u003e0PWN3\u003c\/strong\u003e. Same kit family.\u003c\/p\u003e\n\u003chr\u003e\n\u003ch2\u003eWhich One Do I Need?\u003c\/h2\u003e\n\u003ctable\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003eGoing into\u003c\/th\u003e\n\u003cth\u003eYou need\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e2U PowerEdge with B6 ReadyRails II chassis mounts (R520\/R530\/R540 family, R720\/R730\/R740\/R750 family, R820\/R830, and related — see specs)\u003c\/td\u003e\n\u003ctd\u003e\n\u003cstrong\u003eSliding ReadyRails II (B6)\u003c\/strong\u003e — this product\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSame 2U chassis, but you only need fixed mount (no in-rack service slide-out)\u003c\/td\u003e\n\u003ctd\u003eB4 ReadyRails \u003cstrong\u003estatic\u003c\/strong\u003e rails — \u003cstrong\u003enot this kit\u003c\/strong\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e1U PowerEdge (R620\/R630\/R640 family and similar)\u003c\/td\u003e\n\u003ctd\u003eA7 ReadyRails II 1U sliding rails — \u003cstrong\u003enot this kit\u003c\/strong\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e2-post relay rack, or a chassis that requires VersaRails \/ RapidRails\u003c\/td\u003e\n\u003ctd\u003eDifferent mounting interface — \u003cstrong\u003enot this kit\u003c\/strong\u003e (B6 sliding does not support 2-post)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eYou need organized rear cables while the system is fully extended\u003c\/td\u003e\n\u003ctd\u003eThis kit \u003cstrong\u003eplus\u003c\/strong\u003e the matching optional 2U CMA (sold separately)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003e\u003cstrong\u003eSliding vs static is the first fork.\u003c\/strong\u003e Sliding extends for service and can take a CMA. Static stays put, fits more rack types (including many 2-post installs), and never takes a CMA.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eA 1U chassis does not take this kit.\u003c\/strong\u003e ReadyRails II 1U systems use a different rail identifier (commonly A7). Ordering by “ReadyRails” alone is how wrong-U kits get bought.\u003c\/p\u003e\n\u003chr\u003e\n\u003ch2\u003eTechnical Specifications\u003c\/h2\u003e\n\u003ctable\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003eSpecification\u003c\/th\u003e\n\u003cth\u003eValue\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eDell Part Number\u003c\/td\u003e\n\u003ctd\u003eH4X6X\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCommon Order \/ Alias Numbers\u003c\/td\u003e\n\u003ctd\u003e770-BBIN, 0384R, 0H4X6X, XV104 \/ 0XV104, 0PWN3, 61KCY, MMK10 \/ 0MMK10 (reseller cross-refs also cite 5Y77W, 770-BBKW, 331-4436)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eRail Identifier\u003c\/td\u003e\n\u003ctd\u003eB6\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMounting Interface\u003c\/td\u003e\n\u003ctd\u003eReadyRails II\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eRail Type\u003c\/td\u003e\n\u003ctd\u003eSliding (drop-in inner slides; full extension for service)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eForm Factor \/ U Height\u003c\/td\u003e\n\u003ctd\u003e2U\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eKit Contents\u003c\/td\u003e\n\u003ctd\u003eTwo B6 ReadyRails II sliding rail assemblies · Two hook-and-loop straps · CMA \u003cstrong\u003enot\u003c\/strong\u003e included\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e4-Post Square-Hole Racks\u003c\/td\u003e\n\u003ctd\u003eTool-less\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e4-Post Unthreaded Round-Hole Racks\u003c\/td\u003e\n\u003ctd\u003eTool-less (≈6 mm offset from post vs square-hole flush mount)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e4-Post Threaded-Hole Racks\u003c\/td\u003e\n\u003ctd\u003eTooled — minor conversion; user-supplied screws (#10-32, #12-24, M5, or M6); screw head diameter must be ≤10 mm; screws not in kit\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e2-Post Racks\u003c\/td\u003e\n\u003ctd\u003eNot supported on B6 sliding\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eRail Adjustability (typical B6 group)\u003c\/td\u003e\n\u003ctd\u003eSquare ≈631–868 mm · Round ≈617–861 mm · Threaded ≈631–883 mm (R820\/R830 group uses a slightly deeper min range — verify if rack is shallow)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eRail Depth\u003c\/td\u003e\n\u003ctd\u003e≈714 mm without CMA brackets · ≈845 mm with CMA (per Dell rail sizing matrix)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCMA Support\u003c\/td\u003e\n\u003ctd\u003eOptional CMA mounts left or right without tools — sold separately\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePrimary Compatible Chassis (Dell matrix \/ Dell shop)\u003c\/td\u003e\n\u003ctd\u003ePowerEdge R520, R530, R540, R540xd · R720, R720xd, R730, R730xd · R740, R740xd, R7415, R7425 · R7515 · R820, R830 · Precision R7910 \/ 7920 Rack · PowerVault NX3200 · Compellent SC8000 · related PowerVault\/DR nodes commonly listed with 770-BBIN\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAlso commonly listed (verify on current Dell matrix for your exact SKU)\u003c\/td\u003e\n\u003ctd\u003ePowerEdge R750, R7525 · R550 \/ R550xs (reseller lists; confirm rail identifier B6 on your chassis)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eStatic Counterpart\u003c\/td\u003e\n\u003ctd\u003eB4 ReadyRails static rails\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eStandards\u003c\/td\u003e\n\u003ctd\u003eDesigned for EIA-310 19-inch 4-post racks\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eWarranty\u003c\/td\u003e\n\u003ctd\u003eLifetime, backed by Resilient Tec\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCondition\u003c\/td\u003e\n\u003ctd\u003eNew\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003chr\u003e\n\u003ch2\u003eNote on Sliding vs Static, ReadyRails II vs VersaRails, and 2U vs 1U\u003c\/h2\u003e\n\u003cp\u003eBuyers searching “Dell rails” hit four different products that look alike in a photo: \u003cstrong\u003esliding vs static\u003c\/strong\u003e, \u003cstrong\u003eReadyRails II vs older ReadyRails \/ VersaRails \/ RapidRails\u003c\/strong\u003e, \u003cstrong\u003e2U vs 1U\u003c\/strong\u003e, and \u003cstrong\u003erails-only vs rails+CMA\u003c\/strong\u003e.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eSliding (this kit)\u003c\/strong\u003e fully extends the chassis for service and can take an optional CMA. \u003cstrong\u003eStatic (B4)\u003c\/strong\u003e does not slide for service, does not take a CMA, and covers more rack types — including many 2-post installs. If you never pull the server out on rails, static may be the better buy; if you do, this is the kit.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eReadyRails II\u003c\/strong\u003e is tool-less in square and unthreaded round 4-post racks, with native tooled support for threaded posts after a pin\/latch conversion. \u003cstrong\u003eVersaRails\u003c\/strong\u003e is a different, typically tooled interface (and Dell does not recommend VersaRails in threaded-hole racks). \u003cstrong\u003eRapidRails\u003c\/strong\u003e is square-hole tool-less only. Do not substitute by name alone — match the rail identifier on the chassis docs (\u003cstrong\u003eB6\u003c\/strong\u003e for this product).\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e2U vs 1U:\u003c\/strong\u003e this kit is 2U \/ B6. A 1U ReadyRails II sliding kit is a different identifier (commonly A7) and will not correctly support a 2U chassis. Count the U height on the bezel and the rail identifier stamped on existing rails before you reorder.\u003c\/p\u003e\n\u003chr\u003e\n\u003ch2\u003eGood to Know\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eCMA is not in the box.\u003c\/strong\u003e Dell’s B6 sliding installation guide lists two rail assemblies and two hook-and-loop straps. If you need continuous power\/data while the system is fully extended, order the matching optional 2U CMA separately.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThreaded racks need your screws.\u003c\/strong\u003e For threaded-hole 4-post racks you remove the tool-less pins\/latches and use eight user-supplied screws (#10-32, #12-24, M5, or M6) with head diameter ≤10 mm. Screws are not included.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e2-post racks are a hard no for B6 sliding.\u003c\/strong\u003e If you are in a relay \/ telco 2-post rack, look at the static B4 path (or another Dell-supported 2-post option) instead of forcing this kit.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRound-hole racks sit slightly proud.\u003c\/strong\u003e ReadyRails II in unthreaded round holes offsets about 6 mm from the post vs flush square-hole mount — that also shifts the bezel slightly. Plan door clearance accordingly.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eShallow racks + CMA = depth math.\u003c\/strong\u003e With CMA attached, rail depth is about 845 mm. If you do not need the CMA, removing the outer CMA brackets shortens the rail footprint (Dell cites ≈714 mm without those brackets) and can clear rear PDUs or a tight rear door.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWrong U height is the most common wrong order.\u003c\/strong\u003e H4X6X is 2U. 1U kits, 4U kits, and older RapidRails\/VersaRails kits will not substitute cleanly just because they say “Dell rails.”\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eR820\/R830 use the same B6 identifier\u003c\/strong\u003e but Dell’s sizing matrix shows a slightly deeper minimum adjustability range than the R720\/R740 group. If your rack is unusually shallow, check post-to-post distance against the matrix before you commit.\u003c\/li\u003e\n\u003cli\u003eConfirm the rail identifier in your server’s rack installation section if you are on a less common SKU (storage nodes, Precision rack workstations, later 15th-gen 2U). When the chassis docs say \u003cstrong\u003eB6 ReadyRails II sliding\u003c\/strong\u003e, this is the family.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003chr\u003e\n\u003ch2\u003eQuick Checklist — Is This the Right Kit?\u003c\/h2\u003e\n\u003cp\u003eYou are racking a \u003cstrong\u003e2U\u003c\/strong\u003e Dell system whose docs call for \u003cstrong\u003eB6 ReadyRails II sliding\u003c\/strong\u003e rails (PowerEdge R520\/R530\/R540, R720\/R730\/R740\/R750-class, R820\/R830, Precision R7910\/7920 Rack, NX3200, SC8000, or another B6-listed chassis). Your rack is a \u003cstrong\u003e4-post\u003c\/strong\u003e EIA-310 cabinet with square or unthreaded round holes (or threaded holes where you will supply the correct screws). You want to \u003cstrong\u003efully extend\u003c\/strong\u003e the chassis for service. You understand the optional CMA is separate.\u003c\/p\u003e\n\u003chr\u003e\n\u003ch2\u003eAvailability\u003c\/h2\u003e\n\u003cp style=\"border-left: 3px solid #1e8f5e; background: #f7f8fa; padding: 10px 14px; margin: 14px 0;\"\u003e\u003cstrong\u003eIn stock at Resilient Tec · Additional units ship on a 7–10 day lead time.\u003c\/strong\u003e\u003cbr\u003eOutfitting a row of 2U PowerEdges? Tell us how many chassis and whether you need CMAs and we will quote rails and arms together. \u003ca href=\"\/pages\/request-a-quote\"\u003e\u003cstrong\u003eRequest a quote →\u003c\/strong\u003e\u003c\/a\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWarranty:\u003c\/strong\u003e lifetime, \u003ca href=\"\/pages\/lifetime-warranty\"\u003ebacked by Resilient Tec\u003c\/a\u003e — not a manufacturer term. When a kit fails you reach a named seller in the US, not a ticket queue.\u003c\/p\u003e\n\u003chr\u003e\n\u003ch2\u003eYou Might Also Need\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eOptional \u003cstrong\u003e2U cable management arm (CMA)\u003c\/strong\u003e matched to B6 sliding rails — keeps power\/data connected while the chassis is fully extended (sold separately; confirm the CMA SKU for your generation)\u003c\/li\u003e\n\u003cli\u003eB4 ReadyRails \u003cstrong\u003estatic\u003c\/strong\u003e 2U rails — when you want fixed mount, 2-post flexibility, or no slide-out service\u003c\/li\u003e\n\u003cli\u003eA7 ReadyRails II \u003cstrong\u003e1U\u003c\/strong\u003e sliding rails — only if the chassis is actually 1U, not 2U\u003c\/li\u003e\n\u003cli\u003eUser-supplied rack screws for threaded-hole posts (#10-32, #12-24, M5, or M6, head ≤10 mm)\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"\/pages\/request-a-quote\"\u003eRequest a quote\u003c\/a\u003e — multi-kit \/ multi-rack builds, mixed static + sliding rows, or “I have a chassis tag photo, which rails?”\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"\/pages\/product-guides\"\u003eProduct guides\u003c\/a\u003e — structured rack and cabling notes as we publish them\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003chr\u003e\n\u003ch2\u003eRelated Guides\u003c\/h2\u003e\n\u003cp\u003eDell Enterprise Systems Rail Sizing and Rack Compatibility Matrix (Dell engineering PDF) — rail identifier, adjustability ranges, and CMA depth by platform\u003c\/p\u003e\n\u003cp\u003eDell B6 ReadyRails II sliding rails installation guide — tool-less square\/round install, threaded conversion, and kit contents\u003c\/p\u003e\n\u003cp\u003e\u003ca href=\"\/pages\/request-a-quote\"\u003eNot sure which rail kit matches your chassis tag?\u003c\/a\u003e Send the service tag or a photo of the existing rail stamp (A7 \/ B6 \/ B4, etc.) and we will point you at the correct kit rather than guess.\u003c\/p\u003e\n","brand":"Resilient Tec","offers":[{"title":"Default Title","offer_id":50906168361060,"sku":"H4X6X","price":139.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0767\/3482\/4548\/files\/Screenshot_2026-09-30_164501.png?v=1790801116","url":"https:\/\/resilient-tec.com\/products\/dell-h4x6x-2u-sliding-readyrails-ii","provider":"Resilient Tec","version":"1.0","type":"link"}